Shutter and actuating mechanism for slide projectors



R. L. BURLA May 11, 1954 SHUTTER AND ACTUATING MECHANISM FOR SLIDE PROJECTORS 2 Sheets-Sheet 1 Original Filed June 16, 1950 VNN INVENTOR. RONALD L. BURLA ATTORNEY Patented May 11, 1954 2&71986 SHUTTER AND ACTUATING MECHANISM F93 SLIDE PROJECTORS Ronald L. Burla, Beverly Hills, Caliii, assignor to The Cadwell Corporation, Beverly Hills, Calif., a corporation of California Original application June 16, 1950, Serial No.

Divided and this application March '7, 1951, Serial No. 214,389

2 Claims.

This invention relates to slide exhibiting apparatus and more particularly to means to arrest the projection of the light through the apparatus during the periods in which an exhibited slide is being removed and a slide to be exhibited is being positioned for exhibition.

This application constitutes a division of my co-pencling application Serial No. 168,469, filed June 16, 1950.

Heretofore during the presentation of an illustrated lecture, it has been customary for the lecturer to employ the services of an assistant whose duty it was periodically during the lecture to close the shutter of the stereopticon projector and while maintaining the shutter closed to manually extract from the projector the exhibited slide and to substitute therefor a slide to be exhibited and then subsequently to open the shutter. The slide changing therefor has required several manual operations to be performed in proper sequence and hence the successful operation of the exhibitor or projector required the services of a skilled operator.

The primary object of this invention is to interrupt the projection of light through the exhibitor during the changing of the slides being being changed and thereby to avoid danger of warpage or buckling of the light interrupting shutter.

Another object is to avoid the necessity of employing the services of a skilled operator of the projector apparatus during the presentation of an illustrated lecture or during the exhibition of slides.

The above and other objects may be attained by employing this invention which embodies among its features, a film gate mounted to rock toward and away from an aperture through which light is projected, an injector for moving a slide from the bottom of a stack of slides and advancing it toward the film gate, and means connected to the injector and the film gate for advancing the slide onto the film gate while the latter is away from the aperture.

Other features include an ejector operating across the aperture for displacing an exhibited slide and clearing the aperture for the presentation of another slide thereto and means connected to the ejector and to the film gate, and injector operating means for operating the ejector in timed relation to the movements of the film gate and injector.

Still other features include a shutter for intercepting light projected through the aperture and means operating in timed relation to the operation of the film gate and the injector and ejector for moving the shutter into opening and closing relation to the aperture.

A further and more specific feature is the 10- cating of the shutter between the source of illumination and the condensing system so that the temperature of the shutter remains substantially constant throughout the period of operation of the projector.

Still further features include timing means operatively connected to a prime mover for continuous operation during the operation of the projector for regulating the sequence in which the shutter and the film gate, ejector and injector move.

In the drawings:

Figure 1 is a top plan view of a slide projector embodying the features of this invention, the case being omitted;

Figure 2 is a longitudinal sectional view of the projector taken substantially on the line 2-2 of Figure l;

Figure 3 is an enlarged fragmentary side view of the projector illustrated in Figure l; and

Figure 4 is a horizontal sectional view taken substantially on the line 4@ of Figure 3.

Referring to the drawings in detail a base or bed It has secured thereto a lamp house designated generally 62, the front wall hi of which is provided with an aperture It see Figures 2 and 4, through which light is projected from a source of illumination I8 by a system of condensing lenses 2!].

interposed within the lamp house 52 between the source of illumination i8 and the lens system 28 is a partition wall it having an aperture ll therein which aligns with the lens system 20 and carried by the wall [5 on the side thereof remote from the source of illumination 58 is a pair of spaced vertical guide members It in which is mounted a shutter to be more fully hereinafter described. An elongated vertical slot 2 l is formed in the lamp house I2, the purpose of which will hereinafter appear.

Carried by side flanges Ma of the wall Hi on the side thereof remote from the lens system 28 is a projector housing designated generally 22 comprising spaced parallel side walls 255 and 26 and carried by and extending bet-ween said side walls adjacent the ends thereof remote from the wall 54 is a housing 28 containing a focusing lens system 39 which aligns axially with the aperture [6 above mentioned. Formed at the junction of 3 each wall 25 and 26 with the wall I4 is a vertically extending guide groove 32, the purpose of which will hereinafter appear, and formed between the wall I4 and the housing 28 is a slide receiving chamber 34.

The tops of the walls 24 and 26 are extended upwardly above the top of the focusing lens housing 28 to form guides for the lower end of a magazine 36 containing the slides to be exhibited and the top of the lens housing 26 is substantially flat to form a table 36 upon which rests the lowermost slide in the magazine 36. Carried by the walls 26 and 26 and projecting therefrom in a direction opposite the lamp house I2 is a pair of spaced parallel arms 40 and formed on the inner faces of the arms and extending into the walls 20 and 26 substantially at the level with the table 36 are opposed grooves 42 in which slides the injector, to be more fully hereinafter described. A cover plate 44 is carried by the arms 40 and overlies the injector when the latter is in the retracted position shown in Figure 2, and carried by the cover plate at the end thereof adjacent the table 68 is a pair of spaced upstanding tongues 46 forming guides for guiding the lower end of the magazine 36 into position above the table 38.

Fixed to the bed I below the side walls 24 and 26 is a frame designated generally l0 comprising side plates l2 and I4 held in spaced parallel relation by end plates 16 and I8, and mounted on the bed I0 in outwardly spaced relation to the side plate I2 is an upstanding pedestal 30. A similar upstanding pedestal 82 is fixed to the base 50 outwardly from the side plate 74. These pedestals carry adjacent their upper ends outwardly extending axially aligning pivot pins 84 and 86 respectively, the purpose of which will hereinafter appear.

Mounted in the frame for rotation about a horizontal axis is a drive shaft 88 which projects through the plate I2 and carries adjacent its outer end a drive wheel 60 which has driving connection with a prime mover 92 as by a gear train 64. Fixed to the drive shaft 88 intermediate its ends is a pinion 96.

A driven shaft I00 is mounted in the side plates to rotate about an axis which lies parallel to the axis about which rotates the drive shaft 88. This driven shaft I00 projects beyond the side plate '52 and has fixed thereto for rotation therewith a timing gear I02. The opposite end of the driven shaft I00 projects through the plate 14 and has mounted thereon for rotation therewith and longitudinal sliding movement thereon an arm I06 carrying a laterally extending clutch pin I06. A crank arm I08 is mounted for rotation on the shaft I06 adjacent the extreme outer end thereof and carries an inwardly projecting clutch pin H0 which revolves in an arcuate path concentric about the shaft I00 and corresponds to the path in which the clutch pin I06 revolves. A compression coil spring II2 encircles the shaft I00 between the arm I04 and the crank arm I08 to normally hold the clutch pin I06 out of engagement with the clutch pin I I0 and thus permit the shaft I00 to turn without imparting turning movement to the crank arm I08. Pivotally supported on the outer side of the side plate I4 as at I M for movement about a vertical axis which lies between the shafts 88 and I00 is a trip lever I I6 which engages the arm I04 adjacent the shaft I00 on the side thereof remote from the spring I I2 so that when the trip lever is moved outwardly away from the plate I4 the arm I04 will be 4 i I moved against the effort of the spring [I2 and cause the clutch pin I06 to engage the clutch pin IIO so as to cause the crank arm I08 to rotate in unison with the shaft I00. A trip finger H8 is carried by the trip lever H6 at the end thereof remote from the pivot I I4 and is engaged by the trip cam carried by the timing mechanism yet to be described.

Fixed to the shaft E00 within the frame '10 is a drive gear I20 which meshes with the drive pinion 96 which is fixed to the drive shaft 88.

Mounted in the frame l0 for rotation about an axis which lies parallel with the axes of the shafts 86 and I60 is a timing shaft 48 which projects through the plate I2 and carries adjacent its end a drive gear I56 which has driving connection. with the timing gear I02 through the medium of a gear train I 52. A cam wheel I54 is carried by the shaft I 38 on the outside of the frame I0 adjacent the plate l4 and this cam wheel is provided on its periphery with an outstanding cam I56 the purpose of which will hereinafter appear. A trip can". I53 projects laterally from the cam wheel and moves in a rotary path which intersects the trip finger IE6 so that when. the cam wheel I54 rotates the trip lever H6 will be moved against the effort of the spring I I2 to cause the pin I06 to engage the pin H0 and move the crank arm I08 in unison with the shaft 400 Mounted in suitable brackets I 68, carried by the wall I8, which project rearwardly therefrom on opposite sides of the side walls 20 and 26 is a transversely extending rock shaft I62 which projects beyond the outside of the wall 26 and mounted for rocking movement on the rock shaft I62 is a shutter actuating lever Hi4. One end of the shutter actuating lever I64 is bifurcated as at I66 and mounted for rotation in said bifurcated end I66 of the lever I64 is a roller I68 which rides on the periphery of the cam wheel I54 so that as the latter revolves, the lever I64 will be moved about the axis of the shaft I52 by the cam I56. The opposite end of the lever I64 projects toward the slot 2! in the lamp house and is slotted as at I'I0 to receive an arm I12 extending through the slot 2I and carried by a shutter I14 which is mounted for vertical sliding movement in the guide members I9 carried by the partition wall I 6 for opening and closing the aperture II therein. A retractile coiled spring I76 is connected at one end to the lever I64 intermediate the rock shaft I62 and the slot I10 and the opposite end of said spring is connected to the wall I4 above the lever I64 so as to exert upward pull on the slotted end of the lever I64 and hold the roller I 68 in contact with the periphery of the cam wheel I54. It will thus be seen that the cam wheel !64 revolves with the shaft I46, the shutter I14 will be reciprocated in the guide members I9 to open and close the aperture I I in the wall I5 thus alternately interrupting the light rays emanating from the light source I6 which pass through the aperture I'l.

Mounted for rocking movement on a laterally extending stud I'I6 carried by the well 26 below the cover plate 44, is a V-shaped rock arm designated generally I 80, one leg I62 of which. extends forwardly and upwardly and carries an inwardly extending finger I84. An injector plate I86 is mounted in the guide grooves 42 in the arms 40 and this injector plate carries on the side thereof adjacent the wall 26 and adjacent the end thereof remote from the wall I4 a downwardly extending ear I81 which is provided with an elongated vertical slot I88 in which the finger I84 is received. It will thus be seen that as the rock arm I86 is moved about its pivot N8, the injector plate will be moved across the table 38. When the injector plate :86 moves to the right when viewed as in Figure 2, it will be evident that the bottommost slide in the magazine 36 will be moved rearwardly off of the table 38 and into the chamber 32'. Pivotally connected as at 192 to the arm E22 of the rock arm I80 is one end of a link IN the opposite end of which is connected as at I923 to the crank arm 03 at the end thereof remote from the shaft I00. It will thus be seen that as the crank arm I98 rotates with the shaft Hill the rock arm H80 will be rocked to cause the injector 53% to reciprocate in its guide grooves 12.

In order to catch slides delivered into the chamber 3 from the table 38 and place them in proper position for projection over the aperture It in the wall It the rock shaft IE2 is provided with a film gate comprising a pair of spaced 5 parallel arms E98 which carry spaced parallel leaf springs 2% which form cushions upon which the slides are caught in the chamber 34 and by which a slide is yieldingly held against the wall Is in covering relation to the aperture It therein. A bell crank lever designated generally 202 is fixed to the rock shaft Hi2 adjacent the outer end thereof and one arm 2!! of said bell crank lever extends substantially horizontally toward the lamp house I2 and has connected thereto one end of a retractile coiled spring 2%, the opposite end of which is anchored to the base or bed ill. This spring 226 yieldingly urges the leaf springs 220 of the film gate into yielding contact with the wall id adjacent the apertur It therein.

The opposite leg 228 of the bell crank lever 2B2 extends downwardly and pivotally connected to the lower end thereof, as at 2H], is an arch shaped link 2I2 which extends upwardly and forwardly from the arm 223 to clear the shaft I68. The end of the link 2I2 opposite its pivoted connection with the arm 228 is provided with an elongate substantially horizontal extension 2M having an elongate longitudinal slot 2I$ therein.

A stud 2H3 projects through the slot 2I6 and is fixed in a link 22%) adjacent one end thereof. This link 228 is rigidly connected at I95 to the crank arm fit so as to cause the link 2I2 to reciprocate through a limited distance and cause the arm 252 to rock the shaft I62 and open the film gate formed by the springs 2MB.

In order to eject a slide from its position before the aperture it, in the wall I4, an ejector plate 222 is mounted to slide vertically adjacent the wall I4 in the guides 32 and carried by the ejector plate 222 adjacent the lower corners thereof are forwardly extending ears 224 each of which is provided with an elongate longitudinally extending slot 225. Extending through the slots 226, in the ears 226, is a cross bar 228 and riveted or otherwis secured to the cross bar 228 at the end thereof adjacent the side plate 12 is one end of an arm 232, the opposite end of which is pivotally mounted on the stud it carried by the pedestal all, An ejector actuating lever 232 is riveted or otherwise rigidly secured to the end of the cross bar 228 remote from the arm 23!) and this lever is pivotally mounted intermediate its ends on the stud 85 carried by the pedestal 82. The end of the lever 232 remote from the cross bar 228 is pivotally connected at 234 to the lower end of a link 236, the upper end of which is connected to the pivot Hill at the junction of the arm I92 and the link I94. It will thus be evident that as the pivot I99 moves downwardly under 6 the influence of the link I94, the link 236 will likewise mov downwardly to rock the lever 232 about its pivot 36 and thus cause the ejector 222 to move upwardly in its guide Ways 32.

In operation a magazine containing the slides to be exhibited is placed on the exhibitor with its lower open end disposed between the upper edges of the side walls 2 3 and 26 above the table 33. With the magazine in such a position the bottommost slide in the magazine will rest on the table 38 and the device is ready for operation. The prime mover 92 is then energized, thus causing the drive shaft I38 to rotate the drive pinion 96. Rotation of the shaft lei) causes the timing shaft I 38 to rotate through the medium of the gear train I52 and causes the cam wheel 55 to revolve. As the cam wheel wi l revolves, the roller Hi3 riding on the periphery thereof is engaged by the cam 556 to cause the lever I65 to rock about the shaft i62 and move the shutter PM in its guide Ways to open and close the opening I? in the partition wall It. It is to be noted that the cam I56 is of such a shape that the shutter lid is gradually moved to open position and so held for a period of time suiiicient to give adequate visibility to the slide being projected and that at the expiration of such period, the shutter rapidly moves to closed position. As the cam wheel I52 rotates and immediately after the shutter IN moves to closed position, the trip cam I58 carried by the cam wheel I5 i engages the finger i ii? on the trip lever H6 and moves the trip lever Ht about its pivot El i against the effort of the spring I I2 so as to shift the arm IM and the pin Hi8 outwardly. Such outward movement of the pin I25 causes it to engage the pin Ht on the crank arm I88 so as to cause said crank arm N38 to rotate in unison with the shaft Iilil. The revolution of the crank arm Hill about the axis of the shaft I20 actuates both the slide injector and the ejector mechanism as follows: As the end of the crank arm I88, moves downwardly at the start of its revolution, the pivot connection I96 xerts pull on the link ld i to move the link 236 downwardly and rock the lever 232 so as to cause the ejector 222 to move upwardly in its guides 32 and push a slide held against the wall [4 by the film gate springs 220 upwardly and clear of the apertures It in the wall M. Simultaneously with the downward movement of the link 236, the rock lever 88 is moved about its pivot I18 to move the arm I82 in a clockwise direction and thus cause the injector I86 to ad vance in its guide grooves 52 across the table 38 and push a slide resting thereon into the chamber 34. In the meantime the link 220 will have been moved b the crank arm so that the stud 2 it engages the end of the slot 215 in the extension 2 i l of the link 2 l 2 to exert push thereon and cause th bell crank 222 to rock against the effort of the spring 2%- and move the film gate springs 22!] away from the wall Hi and into a position to receive the slide projected into the chamber 34 by the injector I88. Upon further movement of the crank arm 268, the link 220 will withdraw the stud 2 I8 from contact with the end wall of the slot 2 It and permit the film gate springs to be moved under the influence of the spring 2535, and thus move the slide received by the film gate springs into position before the aperture it. Upon further movement of the cam Wheel I54 the shutter HA- is moved by the cam I56 to open position so that light from the source of illumination will be projected through the slide and the picture thereon will be visible on a screen 7 placed in front of the exhibitor. The various cycles of operation are continuously repeated so long as th prime mover 92 remains energized. In this Way automatic exhibition of slides may be accomplished.

While in the foregoing there has been shown and described the preferred form of this invention, it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

I claim:

1. In a picture slide projector including as a part thereof a projector housing having a wall provided with an aperture before which a slide is held and a focusing lens system in the housing at one side of said wall and aligned with said aperture; a lamp housing upon the opposite side of said wall and having a partition wall therein spaced from the first wall and provided with a light aperture in line with the first aperture, a light source in the housing on the side of the partition wall remote from said projector housing Wall, a condensing lens system between said walls and in line with and between said apertures, vertical guide means within the lamp hous ing on opposite sides of said light aperture and in a plane extending transversely of the lamp housing between the light source and the condensing lens system, a shutter supported by said guide means for vertical movement to cover and uncover the light aperture, a shaft disposed transversely of the housings and extending at one end beyond one side of the housings, an elongate lever pivoted intermediate its ends to said shaft end for rocking movement in a vertical plane, a rotary cam disk supported to turn in a vertical plane beneath one end of said lever and having its periphery in operative connection with said lever end to effect when rotated the rocking of the lever, means for rotating the cam disk, an operative coupling between the other end of the lever and a side of said shutter by which sliding movement is imparted to the shutter upon rocking of the lever, and spring means connected with the lever to maintain said operative connection between the cam periphery and the first mentioned end of the lever.

2. The invention as set forth in claim 1, wherein said operative coupling comprises an arm member secured to a side edge of the shutter and projecting laterally therefrom, said lamp housing having a side wall provided with a vertical slot through which the arm projects to the outside of the latter housing, and said other end of the lever having a slot longitudinally therein in which said arm is loosely engaged.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,247,608 Alguire Nov. 27, 1914' 2,021,963 Owen Nov. 26, 1935 2,401,566 Pechkranz June 4, 1946 

